Luna the high-elf priest goes down to 1100 feet and immediately feels that things are terribly dangerous. A vault maybe? With lucky find of early +5 ring of speed, TO wand and some speed and healing potions, could be doable. What, only scraps of junk? Not a vault then, but maybe some manageable unique with good drops. Or should I just bugger off while I still can?
Decided to investigate. Found room with both Uglug and Lugdush inside with small number of other orcs. Terribly dangerous?? These guys? And they drop nothing worth mentioning.

Still later, pit full of warrior type people. Few ninjas in the center, the rest is easterling muck. Nothing difficult with speed and orb of draining. And when the dust settles, lying on the floor:

Nice! Took a big mana hit though, because it replaced amulet of wisdom +4. No problem though, the men of the east dropped lots of valuables to sell and the friendly black market guy apparently knew this because he had prepared helmet of wisdom with better bonus than my current one and a potion of wisdom. Mana back to just few point below of what it was with wisdom amulet.

Next trip down, a 5-5 level yields this:
Lantern of Perchol
Found lying on the floor in a vault at 1150 feet (level 23)

Themed monster pits and zoos tend to increase the level feeling quite a lot, in my experience. This especially in the early game. OTOH, usually they contain at least a good object, so 7-1 is quite unusual.